Essentialism and graded membership in animal and artifact categories

A number of studies have argued that people view membership in animal and artifact categories as a matter of degree. These studies have generally failed to distinguish between the issues of typicality and category membership. Thus, data which have been taken to demonstrate that membership is a matter of degree may only demonstrate that typicality is graded. Partly on the basis of these findings, it has been argued that some categories are organized around an underlying essence. The essence determines membership absolutely. The present paper reports a series of studies that reexamine the question of graded membership. In the first study, subjects were asked to rate both typicality and category membership for the same stimuli as a way of distinguishing the two questions. A second method relied on the intuition that disagreements about membership in all-or-none and graded categories may have different qualities. Results from both studies suggest some support for claims that membership in animai and artifact categories is a matter of degree. A third study explored the possibility that graded responses were due to conflicting, or ambiguous, sets of criteria. A task focusing on biological features did not lead to more absolute categorization. These results contradict essentialist predictions.     

From fault line to group fission: understanding membership changes in small groups

Group fissions occur when two or more members leave a parent group to either form a new group or join an existing group. This article investigates the interplay between two factors: the presence of an intragroup conflict and subgroup boundaries on the group fission process. It is hypothesized that subgroup divisions act as potential fault lines along which groups split after they experience conflict. The results of three experiments, one scenario study and two laboratory studies involving small task groups, support the group fault line hypothesis. The authors discuss the implications of these findings for theory and research on membership changes in small groups.     

An information-theory approach to geometry for animal groups

Animal Cognition - One of the hardest problems in studying animal behaviour is to quantify patterns of social interaction at the group level. Recent technological developments in global positioning...     

Acoustic interaction in animal groups: signaling in noisy and social contexts

It has long been known that individuals of many species vocally communicate with one another in noisy environments and in rich contexts of social interaction. It has recently become clear that researchers interested in understanding acoustic communication in animal groups must study vocal signaling in these noisy and socially complex settings. Furthermore, recent methodological advances have made it increasingly clear that the authors can tackle these more complex questions effectively. The articles in this Special Issue stem from a Symposium held at the June 2006 meeting of the Acoustical Society of America, and illustrate some of the taxonomic and methodological diversity in studies aimed at understanding how acoustic communication functions in social grouping. This introduction to the Special Issue provides a brief overview of the articles and key ideas in this field of inquiry, and suggests some future directions to take the field to help us understand how social pressures in animal groups may influence, and be influenced by, acoustic signals.     

Redefining the regularity effect

This study reports two experiments that further explore the regularity effect in single-word pronunciation. Experiment 1 shows that regularity effects are found only with irregular words that are “true” exceptions (e.g., PINT, MONK, BROAD). Words that are irregular in terms of grapheme-to-phoneme correspondence rules, but either are regular in terms of a higher order correspondence rule (e.g., PALM, HEALTH) or possess a divergent, although reasonably common, correspondence (e.g., GLOVE, HEAD), produce response times similar to those produced by regular words. These results indicate that the regularity effect is restricted to a smaller set of words than previously has been thought. Experiment 2 examines the regularity effect when subjects are required to delay their responses by 1,500 msec; no difference between exception and regular words is found. This finding indicates that previous demonstrations of the regularity effect cannot be attributed to articulatory differences between exception and regular word samples. Theoretical accounts of the regularity effect are considered briefly.     

Disambiguation by community membership

To interpret utterances in conversations, listeners must often make reference to the common ground they share with speakers. For example, when faced with an utterance such as "That game was a disaster," listeners must decide whether they share common assumptions about what outcome would be disastrous. In our experiments, we examine how common ground, as encoded in community membership, is used to constrain judgments about the interpretations of ambiguous utterances. In Experiment 1, subjects were sensitive to community membership when they were asked to evaluate the interpretations at a leisurely pace. Experiment 2 replicated this result with greater time pressure. Experiment 3 demonstrated that judgments based on assessments of community membership were equivalent to those based on certain knowledge, except when the judgements were challenged. The results suggest that models of memory retrieval during language comprehension should make mention of access to common ground.     

Redefining Work and Education in the Technological Revolution

Studies in Philosophy and Education - Just as Dewey argued during the industrial revolution, from the 1890s–1930s, and Martin argued in the 1960s–1990s with our “second...